1. Field of the Invention
The present invention relates generally to memory cards, systems using memory cards, and an interface method for memory cards. More particularly, the invention relates to a memory card having a separate interface port for transmitting/receiving data at high speed, as well as systems and an interface method associated with such a memory card.
2. Description of the Related Art
Memory cards are portable tokens including a card controller (e.g., a central processing unit (CPU)) and a memory unit capable of storing data received from a host device or data terminal. Contemporary memory cards use memory unit(s) including flash memory. The card controller interfaces with a host device and controls read/write operations that retrieve and store, respectively, data from the memory unit in accordance with command(s) provided by the host. Card controllers often have the capability of executing various applications that implement read, write, erase, data identification, system resource configuration, data security, and other operations associated with the communication of data to/from the memory unit.
Several emerging business models are predicated upon the transfer of “digital content” to a memory card. For example, video clips, audio files, movies, and other voluminous information files may be transferred to a memory card from a vending Kiosk using automated systems. That is, a user may insert his memory card into an automated Kiosk and use an information transmission system including a simple graphical user interface to download selected digital content to his memory card. Such business models offer ease of use, low cost convenience, and improved security as compared with open transmission media such as wireless or the Internet.
Given its voluminous nature, the speed with which the digital content may be downloaded to the memory card is crucial to the success of the business models. Conventional memory cards are configured to transmit voluminous data bi-directionally (read and written) by sharing a common bus instead of uni-directionally via separate buses.
Figure (FIG.) 1 illustrates the structure of a conventional memory card 10. Referring to FIG. 1, conventional memory card 10 includes an interface port for data communications with a host. The interface port is typically implemented through at least one pad 11. The interface port allows memory card 10 to receive a power voltage VDD, a ground voltage VSS, various command signal(s) CMD, a clock signal CLK, and a data DATA. Memory card 10 is also able to communicate data to a host device via the single interface port.
In many applications, a memory card is used in conjunction with a battery powered mobile device. Such applications have traditionally restricted the ability of the memory card to download large volume digital content, because high-speed data communications result in significant consumption of battery power. Additionally, the use of a single interface port facilitating bi-directional data transmissions between the memory card and host places significant practical limitations on the speed with which digital content may be downloaded. The foregoing limitations on the speed with which digital content may be downloaded adversely effects the profitability of the emerging business models.